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Voodoo Shack: When Voodoo is what you do™

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V5 Overclocking

All performance graphs courtesy of Bonehed.

There has always been a question as to the overclocking potential of the Voodoo5. When it first came out, many reviewers were very disappointed with it's ability in this area, and quickly wrote it off as a non-overclocker friendly card. There does seem to be some evidence which shows this to be the case, but part of the blame can probably be attributed to the very small heatsink/fans that the stock V5 comes with. Many have had a great deal of success overclocking by simply changing out the tiny heatsinks for more robust units. The average overclock of the V5 5500, for example, seems to be around 176MHz or so with OEM equipment.

Also, it seems that there is a trend of first run production cards to not overclock as well as later revisions. This was true in the case of the Voodoo3 as well, with most V3 3000's only overclocking to 176-180MHz, while later chip yields and higher quality SDRAM allowed last run production cards to often overclock well above 200MHz. Unfortunately for owners of V5 5500's, the card was produced for less than 6 months before 3dfx went out of business, so the likelihood of finding good overclocking, high yield GPU(s) is slimmer than in the case of previous 3dfx cards. Some (like myself) tried nearly everything, including modding the card with huge heatsinks, large fans, and ram sinks. And yet the overclocking potential of the card proved to be nearly the same as stock.

When I first purchased my V5 5500 back in 2000, I was very intent on overclocking the beast. It was one of the first run series, and came with the 1.06 BIOS and 6ns Hyundai SDRAM (previously hailed as the memory of choice on the V3). Alas, my V5 5500 would overclock stable only to about 175MHz when first purchased. I, ofcourse, being the tweak/overclock nut that I am, immediately ripped off the stock equipment, and went to work. I first removed the factory thermal epoxy by taking an old washcloth and some finger nail polish remover (acetone based), and vigorously rubbed both GPU's until the material was thoroughly removed. Then I lapped the GPu's with fine grade sandpaper until perfectly smooth, and finally applied Arctic Silver thermal compound to massive heatsink/fans on both GPU's. I also applied thermal goop to ramsinks, which I affixed to all SDRAM chips. To make a long story short, after all the modifying, I still could only achieve around 180MHz stable. All that work I performed (and expense) for only 5MHz increase did not a happy camper make.

Fast forward to the present, and center stage my buddy Bonehed, a regular Zealot on the x3dfx Forums. He had this great idea of modding the card simply with fans on the back of both GPU's. It seems that the back of the card gets VERY hot, and this can really limit the overclocking no matter what you mod elsewhere. Here's the back of Bone's V5 5500:

CLICK FOR LARGER IMAGE

Note the use of masking tape affixed to the card. :) This allows the fans to be superglued to the tape, and not the PCB, making for easy removal later. Bone used huge Celeron fans, and has been able to overclock up to 189MHz using this method.  He also has modded his V3 3000 AGP in similar fashion with a single fan, and has attained a truly remarkable 212MHz overclock!

CLICK FOR LARGER IMAGE CLICK FOR LARGER IMAGE

Extrapolating on Bone's idea, I used some double sided foam "Supermount" tape, available at your local Radio Shack, part #64-2344. I simply cut the tape into 4 very small triangle shapes, and affixed the heatsinks to the PCB with tape on all four corners. Worked perfectly, and it's firm enough to allow semi-permanent mounting of the heatsinks, but still allows removal later without to much hassle. So how did she do? 183MHz was possible now in most applications, although GLIDE was still a bit fickle for some reason. In any event, I got a better overclock using Bone's simple procedure than I did with all the mods I did before (with the same exact card). Here's some benchmarks in Q3A to show the types of gains that are possible when overclocking your Voodoo5.

Test System:
P3 1000/133 1.75v, cD0 core
Soyo SY-6BA+IV i440BX, UDMA66
256MB Corsair PC100 @ 133MHz CL3
Quantum Fireball AS 7200RPM, UDMA66
Voodoo5 5500 AGP, BIOS 1.15, Hyundai 6ns SDRAM
Win98SE, Q3A 1.17, ICEMAN 1.07.01 V5 driver kit

Q3A Demo001, Hiquality sound

1024x768x32 HiQ
166 = 74.5
175 = 78.2
183 = 82.4 +9.7%

800x600x16 4x FSAA Normal
166 = 47.0
175 = 49.2
183 = 51.9 +9.5%

1600x1200x16 Normal
166 = 44.1
175 = 46.1
183 = 48.7 +9.4%

It appears that a 10% overclock yields an average of a 9.5% performance increase in all fill-rate limited situations. This is almost a perfect 1 for 1 in terms of overclock percentage vs performance percentage increase. If we can extrapolate on the data gathered, it can be deduced that performance potential for those lucky enough to have high-yield GPU's can be fairly considerable:

166 x 10% overclock = 182.7MHz (as above) = +9.5% average performance increase
166 x 20% overclock = 199.2MHz = +19% average performance increase

If we continue to use this line of reasoning and taking the numbers achieved in the benchmarks above, my system as listed might possibly achieve the following with a 200MHz overclock:

1024x768x32 HiQ
200 = 88.95 +19.4%

800x600x16 4x FSAA Normal
200 = 55.95 +19%

1600x1200x16 Normal
200 = 52.47 +18.8%

And to summarize the results:

V5 Overclock.jpg (23861 bytes)

Ofcourse, this is all conjecture and theory since my poor little V5 can only attain 183MHz, but there are certainly some people out there with cards that should manage 200MHz with proper cooling and alot of luck. As always, your mileage may vary, but this provides some ideas for those looking to overclock their Voodoo5 5500. Rather than modding the heck out of your card, you may get good results using Bonehed's method of cooling the back of the GPU. I know I did.

Copyrightę 2002 Nightstormer Productions